1. Field of the Invention
The present invention relates to information processing apparatuses and methods for controlling the information processing apparatuses.
2. Description of the Related Art
There exists an information processing apparatus that enters a power-off mode when it is detected that the apparatus is left unoperated for a predetermined period of time (i.e., auto power-off). In the power-off mode, a power supply switch of the apparatus is turned off to shut down the power supply.
According to a technique discussed in Japanese Patent No. 3,564,925, if it is detected that an apparatus is being left unoperated for a predetermined period of time (i.e., auto power-off time), a power supply switch is turned off (i.e., auto power-off). Then, a time that has elapsed from the auto power-off until turn-on of the power supply switch is measured (i.e., measurement time). If the sum of the measurement time and the auto power-off time falls below a reference value, the auto power-off time is corrected so that the sum exceeds the reference value.
However, according to the technique discussed in Japanese Patent No. 3,564,925, even if a short duration is set as the auto power-off time when use of the apparatus is started, at the time that the auto power-off is repeated, the auto power-off time may be extended. Then, if the auto power-off time is long at the time that use of the apparatus is finished, the apparatus may be powered off after being left unoperated for a long period of time.
On the other hand, there exists an apparatus that enters a sleep mode, when it is detected that the apparatus is being left unoperated for a predetermined period of time, in order to suppress power consumption of the apparatus (i.e., auto sleep). Many apparatuses enable a user to set such a predetermined period for the sake of convenience.
There also exists a technique in which time to finish using an apparatus is preset and a power supply switch of the apparatus is turned off at the predetermined time to shut down the power supply (i.e., time specifying power-off).
If the power supply is shut down through the auto power-off, a user needs to manually turn on the power supply switch to use the apparatus again. Therefore, the user tends to set the auto power-off time longer in order to avoid such a situation. In this case, unnecessary power is consumed for a long period of time until the power supply is shut down.
Furthermore, if a plurality of users shares an apparatus, it may be difficult to determine which user is the last one to use the apparatus, and thus none of the users manually turns off the power supply switch, and the apparatus may be left without shutting down the power supply. Therefore, the power supply switch of the apparatus may be turned off through the time specifying power-off. However, the user may turn on the power supply switch after the time specifying power-off to use the apparatus.
As mentioned above, it is possible that a user who normally does not turn off the power supply manually after use of the apparatus, may turn on the power supply switch after the time specifying power-off. In this case, the user may leave the apparatus as it is after finishing an operation of the apparatus. In such a case, since it is possible that a plurality of users shares the apparatus, the apparatus is first brought into the sleep mode through the auto sleep processing. Then, the power supply may be shut down through the auto power-off, or if a user continues using the apparatus, control may be carried out so that the power supply is not shut down until the next specified time. However, also in this case, the apparatus is left in the sleep mode for a long period of time until the power supply is shut down through the auto power-off, resulting in unnecessary power consumption.